I use the WLF Enduro Pack Vest, and it is next level! It is insanely comfortable and made of a strong, waterproof cordura material with several storage areas for everything you could possibly want or need on a trail ride. It uses YKK zippers and is covered in molle webbing. It is the most versatile riding pack on the market! It holds up to a 3L hydration bladder also. I love the functional design and how the weight is off of my shoulders.
I carry 2L of water, Stihl foldable trail saw, a lighter, wrenches, metric and hex sockets, small 3/8 drive ratchet, Tusk mini T-handle, Tusk front/rear axle wrench wrapped in electrical tape, zip ties, spark plug, spare master links, 2 tire gauges, spare pair of goggles, gloves, 2 microfiber rags, a set of each 12"/20" straps, JB Weld, snacks, and my phone/wallet/keys.
Aside from first aid supplies and a tow strap, what do you carry on rides that I should add to my Pack Vest to be prepared for any situation?

